The problem is that the !set command skips any extra spaces given after the setting name.
To work around it you could add a dot or a non-breaking space on the location of the *:
!set reg_msg *
Nickname: %[user_name]
Password: %[password]
Profile: %[user_profile]
Hubname: %[hub]
Hubaddress: adcs://%[address]
Alternatively, you can use a tab in front of the lines instead of spaces.